The present invention generally relates to the automatic control of an appliance. More specifically, the present invention relates to a method and control module for controlling the operation of the defrost cycle of a refrigerator based upon the time of day such that the defrost cycle will not activate during peak demand times.
Currently, rolling blackouts are occurring in parts of the United States because of large energy requirements versus short energy supplies occurring during peak demand times. In states that are experiencing rolling blackouts, incentives are given to energy consumers for reducing the use of energy during such peak demand times.
Currently available domestic frost-free refrigerators defrost approximately once per day, which creates a 300-500 watt load during the defrost cycle. Most frost-free refrigerators use an electromechanical timer with switching to run a defrost heater that is placed around the refrigerator evaporator coil. The electromechanical timer is configured to switch to the defrost operation after a certain amount of compressor run time (typically 6 to 12 hours). Thus, the triggering of the defrost cycle is based upon the run time of the compressor, such that the defrost cycle can occur at any time during the day and at different times on a day-to-day basis.
Due to the energy supply problems in several states, a need exists for a control module that prevents the operation of the defrost cycle of a frost-free refrigerator during peak demand times. Further, a need exists for a defrost timer that can be retrofit onto frost-free refrigerators currently in use. It is an additional object of the present invention to provide a defrost delay control module that learns the defrost cycle of the current defrost timer and prevents the activation of the defrost heater during peak demand times.
The present invention relates to a device and method for automatically defrosting a refrigeration system only during non-peak energy demand. The device includes a defrost module that plugs into the current electromechanical defrost timer supplied with frost-free refrigerators. The delay module includes a microprocessor and uses a clock or timekeeping device to delay the power consuming operation of defrosting a refrigerator or freezer. The intent of the invention and device is to reduce appliance power consumption during peak power requirement times. The method of the invention includes the step of delaying the defrost cycle, which uses a defrost heater element and requires energy to heat the appliance, followed by the consumption of additional energy to operate the compressor to cool off the product once the defrost cycle is completed, to a time when power consumption is not at its peak use.
The delay module of the invention includes a microprocessor that monitors the operation of a defrost timer for several cycles of operation such that the delay module can learn the specific operating parameters for the defrost timer. Once the operating parameters are learned, the defrost timer monitors the compressor run time and anticipates the defrost cycle and prevents the defrost cycle if the defrost cycle will occur during peak power consumption periods. If the defrost is delayed, the delay module will reapply power to the timer motor of the defrost timer once the peak period has passed.